1. Field of the Invention
The present invention relates to an apparatus and a method for processing a video signal for displaying a video signal onto, for example, a flat panel type display, and specifically, relates to an improvement in generation of a new pixel for the apparatus, and the method related thereto.
2. Description of the Related Art
In recent years, a flat panel type display using, for example, a liquid crystal panel or a plasma display panel has become widely used. For this kind of display, a video projection type, or so called projector tends to become widely used.
Incidentally, such a flat panel type display generates a new pixel from a pixel of an input video signal by using a weighting filter so as to conduct so-called scaling for matching the number of pixels of the input signal to the number of pixels of a display panel.
However, according to a conventional scaling means, it is likely to make scaling strips be thick and stand out, if scaling in which the number of pixels to be newly generated is close to that of an original pixels, that is, scaling with a low magnification such as scaling of 1.1 times is conducted.
This is because a property of the weighting filter, in the case of generating a pixel at an intermediate point between adjacent original pixels, is different from that in the case of generating a pixel at a position matched to that of the original pixel. In other words, in the case of generating a pixel at the intermediate point of the adjacent original pixels, a low pass characteristic of the weighting filter becomes stronger than the case of the generation of the pixel at the position matched to that of the original pixel.
As mentioned above, when the low pass characteristic of the weighting filter is varied in accordance with the generated pixels, a section with noise greatly reduced therein and a part with the noise slightly reduced therein are respectively generated, so that intensities of the two types of noise are shown as stripes. Especially, in the case of low magnification scaling, the intensities of the two types of noise are shown as stripes with noticeable thickness.
A configuration for selecting interpolation coefficients from a reference table on the basis of address positions set in response to magnification is disclosed in Jpn. Pat. Appln. KOKAI Publication No. 2002-374407. In this configuration, the reference table with a plurality of interpolation coefficients for conducting interpolation processing by multiplying them by an adjacent plurality of pixels stored thereon is prepared, by corresponding to each address position at which the intervals of the adjacent pixels of the original pixel are divided into the number n, respectively. However, the technique for scaling by generating the new pixels from the original pixel is sill in a developing stage and it is therefore strongly desired to develop a method further appropriate for practical use in respect of a variety of points.